Magnetite containing catalyst for the synthesis of hydrocarbons



Patented Jan. 1951 PATENT oFFipE MAGNETITE con'rsmmo oA'rALYs'r FOB "ran srn'rmasrspr nYnnocABnoNs Jerry A. Pierce, Baton Rouge, La., asslgnor to Standard Oil Development Company, a corporation of Delaware iNo Drawing.

actions and/or in the production of hydrocarbons, and oxygenated hydrocarbons from reactants containing carbon monoxide and hydrogen, in a synthesis reaction.

Not many catalysts are known to be useful in hydrocarbon synthesis employing carbon monoxide and hydrogen as reactants. In the earlier work in this field cobalt carried on a suitable support, such as kieselguhr, and activated by certain materials, such as thoria,-was used as a catalyst; Later, iron catalysts were used in thehydrocarbonv synthesis reaction and in many respects these catalysts are superior to cobalt catalysts in processes designed" to produce good quality gasoline. In other words, where the catalyst is cobalt the product of the synthesis'com' tains mostly straight chain parafllns and paraflin wax. The process employing iron forms a gasoline product highly oleflnic and, therefore, of high I have reviewed briefly the prior art relating to hydrocarbon synthesis. To explain my present invention more fully, it should ybe pointed out that my improvements, relate primarily to powdered metal catalysts to be employed in socalled fluid catalyst type of operation. By fluid catalyst operation, I refer to a process in which powdered catalyst is suspended in the gasiform material in the reaction zone to form a dense, turbulent ebullient suspension of solids in gasiform material. This-suspension is formed by controlling the superficial velocity of the gasiform material, etc, passing upwardlyin the reaction zone. Broadly, this technique is-known in the prior art and practiced commercially in catalytic cracking. However, my catalysts may be used in the form of pills and/or granules and employed in a stationary bed or beds of catalyst, in

the reaction zone, rather than employed in the fluid bed processpreviouslymentioned.

One object of my invention is to prepare a catalyst adapted to catalyze the reaction between Application September 12, 1946, Serial No. 696.627

roams. 1(01. zen-449.

carbon monoxide and hydrogen to form hydrocarbons and oxygenated hydrocarbons, or to .hydrogenateor dehydrogenate hydrocarbons and oxygenated hydrocarbons. 5 Another object of my invention is to prepare an ironhydrocarbon synthesis catalyst adapted for use in powdered form in a fluid catalyst process. Another object of my invention is to prepare an iron catalyst adapted for use in a hydrocarbon synthesis process, which catalyst isresistant to attrition, retains its activity for anextended period of time, is selective in itsaction and may be used without promoters. l6 Other and further objects of my invention will appear from the following 'more detailed description and claims.

To'the accomplishment of the foregoing and related ends, I prepare a metal catalyst by reacting metallic oxides with aluminum under conditions more 'fully explained hereinafter.

Now while as indicated, my process is of general application, an important aspect of it relates to preparing iron catalysts adapted for use in hydrocarbon synthesis and I shall proceed to describe one preferred modification of my invention in terms of itsapplication to hydrocarbon synthesis with the understanding that the principle of my invention includes other reactions, such as hydrogenation and dehydrogenation of hydrocarbons, ketones, organic acids, etc. In preparing an iron catalyst adapted for use in hydrocarbon synthesis I mayproceed according to the following specific examples.

Example 1 Example 2 V Example 1 was repeated,but 10 parts by weigh Cu0 and 1 part MnO were mixed with '77 parts FzOa and 13 parts Al (powder). The finished product had physical properties similar to the product of Example 1.

Example 3 Six parts by weight of aluminum powder were be mixed with 95 parts of maenetite (FeaOt).

. vantage.

' (These proportions represent about one-half of the stoichiometric amount of A1203). When ignited, this product did not burn with fthe violence displayed'in the process of Example '1, and'combustion had to be maintained by means of an external flame. The resulting product was nodular in form, resembling Brain Coral. It was brittle and easily broken into granules but had a hardness of seven and scratched glass. It was also highly magnetic.

I may use any oxide of iron, 1. e., FeO, FezOa. or Fea04, being careful to use an amount of aluminum powder which will react with' about 50 per cent of the oxy en.

This catalyst (Example 3) was tested in. a

hydrocarbon synthesis reaction under the following conditions and with the below results:

Temperature in the reaction zone 600 1''. Pressure in the reaction zone 250 lbs. Ratio of H2 to'CO- (volumetric) in feed 2.1 to 1 Per cent CO converted 92 Yield of liquid product per cubic meter of (H2+CO) measured at 60 F. and

1 atmosphere pressure L--- 08 cc.

If the materials are present in stoichiometric quantities, a fused mixture of alumina (A1203) and metallic iron is the product. If aluminum is in excess, a homogeneous mixture of aluminum, alumina and alloy is formed. If, on the other hand, a smaller quantity of aluminum is used, a mixture of alumina, iron and magnetite results. If it is found that NazO, KF or other chemicals are of value as promoters, the compound which will produce such a promoter after heating is included in the mixture and fused with the main ingredients. It is thus possible to blend these foreign materials to the best ad- In all cases the cooled product is a hard, porous substance resembling slag or lava. It can easily be broken up to pieces of the desired size, but is resistant, nevertheless, to attrition. The hardness of the usual product is, as stated, about 7 i. e., it scratches glass but'is not easily scratched by a file. Most products are strongly magnetic.

On the surface the method employed is similar to the well-known thermit process used for welding. However, the thermit mixture is one which results mostly in metallic iron, which is not porous or easily granulated, and does not contain slag.

I have found that the use of iron oxides is not essential in the production of catalysts by my method and that oxides of Cr, Co, Th, Ni and Cu may be used, either alone or incombination.

I also do not wish to be limited to the process which uses the oxidation of aluminum in the presence of oxides by induced combustion to produce these catalysts. Aluminum and metallic oxides may be heated in a furnace at controlled temperatures to produce my catalysts.

By a similar procedure, I may reduce other metal oxides to produce, say, copper, nickel, chromium, etc., in a physical form more suitable for use as a catalytic material.

To recapitulate, I have found a method for producing catalysts in a form more suitable as catalysts. I fuse aluminum in powdered form' 1 n the mineralogical scale (on the scale, talc=1, diamond=10).

Yields. of ever 200 cc. per cubic meter of (Hg+) are considered good in the present art.

with a heavy metal oxide in various proportions and form a catalytic material resistant to attrition, yet capable of being ground to a powder.

' I have found that a mixture containing from 10 to weight per cent aluminum (the balance being F8203) gives an active catalyst when treated as above, 1. e., reacted together to form metallic iron and A1203. Higher percentages of aluminum aswell as lower percentages give a less active" catalyst. Best results are obtained mix-' ing 13 per cent powdered aluminum with 87 per cent F820: and causing the above reaction to take place.

In preparing the catalyst, ignition may be started as by momentary contact with the flame of an acetylene torch. Where 18 to 54 per cent aluminum powder is present, combustion sustains itself after ignition. with the 13 per cent aluminum content, it is necessary to apply a flame until the top layer has been melted, after which the reaction will be self-sustaining.

By proper known procedures my'catalyst may be formed into pills, pellets, powder, macrospheres, or microspheres.

Instead of using powdered aluminum, I may use powderedamorphous silicon.

216 to 227 cc. of a. liquid product (C4+hydrocarbons) per cubic meter of CO+H2 were obtained. These yields were obtained in both fixedbedand fluid catalyst processes and are considered good. The amount of aluminum used corresponds to one-half the theoretical amount required in the equation:

Feio=+2Ai=2Fe+A1=o= Numerous modifications of my invention may be made by those skilled in the art without aeparting from the spirit thereof.

What I claim is:

1. The method of forming hydrocarbons and oxygenated hydrocarbons synthetically which comprises reacting carbon monoxide and hydrogen in the presence of a catalyst consisting essentially of alumina, iron metal and magnetite formed by reacting iron oxide with about onehalf of,its stoichiometric weight of powdered aluminum by a reaction wherein at least a portion of the heat requirements are supplied from an external source, at elevated temperatures and pressures, and thereafter grinding the product to a powder, the catalyst being in the form of a fluidized mass in the reaction zone.

2. The method of forming hydrocarbons and oxygenated hydrocarbons synthetically which comprises reacting carbon monoxide and hydrogen in the presence of a fluidized. catalyst consisting essentially of alumina, iron metal and magnetite in a reaction zone by charging a mixture of carbon monoxide and hydrogen to said reaction zone maintained at an elevated temperature and pressure which are suitable for said reaction in -the presence ofan iron catalyst and permitting the reactants to remain in the reaction zone for a sufllcient period of time to effect the desired conversion, the catalyst being vated temperatures, with about twice its stoichiometric weight of FezOa to form a hard, brittle vmass, which mass is ground to a powder, at

least a portion of the heat requirements for said catalyst formation reaction being supplied from an external source.

3. The method set forth in claim 2 in which the amount of aluminum reacted is from 10 to 18 weight per cent of the total of the iron oxide and the aluminum.

4. The method of claim 2 in which the catalyst is formed by reacting 13 weight per cent powdered aluminum with 87 weight per cent of FezOa.

5. The method set forth in claim 1 in which the catalyst contains a promoter comprising a potassium compound.

6. The method set forth in claim 2 in which the catalyst contains a promoter comprising a potassium compound.

7. The method of forming hydrocarbons and oxygenated hydrocarbons which comprises contacting at an elevated temperature of at least about 500 F. a gas mixture containing carbon monoxide and hydrogen with a catalyst consisting essentially of alumina, iron metal and mag- 6 netite formed by reacting powdered aluminum with FezOa, the amount of aluminum powder being from 10 to 20 weight per cent of the alumihum-iron oxide mixture and at least a portion of the heat requirements of said catalyst-forming reaction being supplied externally.

JERRY A. PIERCE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Roberts Feb. 15, 1949 

1. THE METHOD OF FORMING HYDROCARBONS AND OXYGENATED HYDROCARBONS SYNTHETICALLY WHICH COMPRISES REACTING CARBON MONOXIDE AND HYDROGEN IN THE PRESENCE OF A CATALYST CONSISTING ESSENTIALLY OF ALUMINA, IRON METAL AND MAGNETITE FORMED BY REACTING IRON OXIDE WITH ABOUT ONEHALF OF ITS STOICHIOMETRIC WEIGHT OF POWDERED ALUMINUM BY A REACTION WHEREIN AT LEAST A PORTION OF THE HEAT REQUIREMENTS ARE SUPPLIED FROM AN EXTERNAL SOURCE, AT ELEVATED TEMPERATURES AND PRESSURES, AND THEREAFTER GRINDING THE PRODUCT TO A POWDER, THE CATALYST BEING IN THE FORM OF A FLUIDIZED MASS IN THE REACTION ZONE. 